Updated Film & Screenwriting Tool

Movie Runtime Split Calculator

Split any movie runtime into Act 1, Act 2A, Act 2B and Act 3. Use a standard four-part act structure or define your own custom percentages to get clean timestamps for key story beats in hours and minutes.

Act 1 / 2A / 2B / 3 Standard Structure Custom Percentage Splits Timestamps in HH:MM

Break Down Movie Runtime into Acts and Story Beats

This Movie Runtime Split Calculator offers two modes. The Standard Act Structure tab uses an even four-part split (Act 1, Act 2A, Act 2B, Act 3), while the Custom Split tab lets you specify your own percentages for each act. Both modes return exact durations and timestamps so you can plan beats, scenes and turning points with a clear time map.

Enter the total runtime of your movie, including or excluding end credits depending on how you like to plan. The calculator converts everything to minutes internally and then back to HH:MM timestamps for each act.

Act 1, Act 2A, Act 2B and Act 3 each get 25% of the runtime.

In this standard mode, the movie is split into four equal quarters: Act 1, Act 2A, Act 2B and Act 3. This is a simple, practical approximation of the common 3-act structure with a midpoint split in Act 2.

The four percentages must add up to 100%. This mode is useful if you prefer a different structure, such as a longer Act 2 or a shorter Act 3. The calculator will normalize small rounding differences automatically.

Movie Runtime Split Calculator – Act 1 / 2A / 2B / 3 Breakdown

The Movie Runtime Split Calculator on MyTimeCalculator is designed for screenwriters, editors, filmmakers and story analysts who plan in time, not just pages. Instead of manually dividing your movie clock with a spreadsheet, you can enter the runtime once and instantly see how much time each act gets and where key beats fall in the timeline.

The calculator supports a simple four-part model: Act 1, Act 2A, Act 2B and Act 3. This matches a common way of thinking about the classic 3-act structure with a midpoint split in the long middle act.

1. Standard Four-Part Act Structure

In the Standard Act Structure tab, the runtime is divided into four equal quarters:

  • Act 1 (Setup): 25% of the runtime, from the opening to the first major turning point.
  • Act 2A (Early Confrontation): 25%, from the Act 1 break to the midpoint.
  • Act 2B (Late Confrontation): 25%, from the midpoint to the Act 2 break.
  • Act 3 (Resolution): 25%, from the Act 2 break to the ending.

This is not the only way to break down a film, but it is a practical, easy-to-remember default for planning beats and checking pacing against a typical commercial movie length.

2. Custom Act Splits

Different genres, styles and mediums can benefit from different act proportions. For example, you may want:

  • A shorter Act 1 for a fast-paced thriller.
  • A longer combined Act 2A+2B for a character-driven drama.
  • A compact Act 3 for a tight ending.

In the Custom Split tab, you can enter four percentages that add up to 100%. The calculator then:

  • Converts the total runtime to minutes.
  • Computes the exact duration of each act based on your percentages.
  • Generates HH:MM timestamps for the end of each act.
  • Displays everything in both minutes and formatted times.

3. How the Movie Runtime Split Calculator Works

  1. Runtime input: Enter total hours and minutes. The calculator combines them into a single value in minutes.
  2. Choose structure: Use the Standard tab for an even four-part split, or the Custom tab to define your own percentages.
  3. Convert to act durations: The tool multiplies the total runtime by each act percentage to get act durations in minutes.
  4. Build timestamps: By accumulating the act durations, it calculates the HH:MM time at which each act ends.
  5. Display results: The calculator shows durations and end times in both minutes and neat HH:MM format, plus a short textual summary.

4. Practical Uses in Screenwriting and Editing

  • Outlining: When outlining a script, you can quickly see where Act 1 should end or where the midpoint falls in the runtime you are targeting.
  • Beat sheets: Translate standard page-based beat sheets into time-based markers for table reads, rehearsals or editing sessions.
  • Editing and pacing: In post-production, you can compare your actual cut lengths to the theoretical act durations and see if certain sections are running long.
  • Teaching and analysis: Use the calculator as a teaching aid when analyzing structure in existing films or discussing pacing in class or workshops.

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Movie Runtime Split Calculator FAQs

Frequently Asked Questions

Quick answers to common questions about movie runtimes, act structures and how to use the Movie Runtime Split Calculator for planning and analysis.

It depends on what you are planning. Many writers and editors focus on the “story content” runtime and ignore long credit rolls. If you are primarily concerned with act breaks and narrative beats, you can enter the runtime without credits. If you are scheduling a screening or broadcast slot, you may want to include the full runtime so the final timestamps match the actual playtime on screen.

No. The equal four-part split is a simple, practical guideline rather than a strict rule. Many films use a longer combined Act 2, a shorter setup, or an extended ending. That is why the Custom Split tab lets you specify whatever percentages fit your story. The calculator is there to support your chosen structure, not enforce a single formula for all movies.

The timestamps are mathematically precise for the runtime and percentages you enter, but real cuts and scene transitions rarely align to the exact minute. Think of these markers as targets or guidelines: a midpoint at 56:00 in the calculator might translate to a key scene somewhere around the 55–57 minute mark in the actual edit. The numbers help you see the structure clearly while allowing creative flexibility.

Yes. The calculator simply works with total runtime and percentages, so you can use it for TV episodes, web series episodes, short films or any other audio-visual format. For multi-act TV scripts with ad breaks, you can treat each “act” in the calculator as one of your segment blocks and choose percentages that match your format requirements or network guidelines.

The calculator checks the total and will warn you if the sum is far from 100%. If the difference is very small (for example due to rounding like 24.9 + 25.1 + 25 + 25), it can normalize internally so that the acts still cover the entire runtime. For best results, adjust your inputs so the four percentages add up to exactly 100% or very close to it.